O emprego da moldagem digital na prática odontológica - relato de caso / The use of digital molding in dental practice ­ case report

O avanço da tecnologia de digitalização de imagens e desenvolvimento de dispositivos de fresagem possibilitaram a otimização de diversos processos na Odontologia. O emprego do escaneamento intraoral e do sistema CAD-CAM (CAD - Computer Aided Design; CAM - Computer Aided Manufacturing) aprimorou a realização de reabilitações protéticas, permitindo a obtenção de peças de alta qualidade em tempo reduzido. O objetivo deste trabalho é relatar um caso de reabilitação de um incisivo central inferior a partir de escaneamento intraoral, com scanner Omnicam (DentsplySirona Charlotte, NC, EUA) e aplicação do sistema CAD-CAM.

The advancement of image digitization technology and the development of milling devices have made it possible to optimize various processes in Dentistry. The use of intraoral scanning and the CAD-CAM system (CAD - Computer Aided Design; CAM - Computer Aided Manufacturing) has improved the performance of prosthetic rehabilitations, allowing the obtaining of high quality parts in a reduced time. The objective of this work is to report a case of rehabilitation of a lower central incisor using intraoral scanning, with an Omnicam scanner (Dentsply Sirona) and application of the CAD-CAM system.

Exploration of the mechanism underlying the therapeutic effect of electroacupuncture at chengshan acupoint on post-hemorrhoidectomy anal pain: Insights from the mAChRs/IP3-Ca2+-CaM signaling pathway.

OBJECTIVE: In the context of postoperative anal pain, understanding the intricate mechanisms and effective interventions is paramount. This study investigates the role of Muscarinic Acetylcholine Receptors (mAChRs) and the IP3-Ca2+-CaM signaling pathway in a rat model of postoperative anal pain, exploring the potential analgesic effects of electroacupuncture. METHODS: Comprehensive approaches involving mechanical sensitivity assays, Western blotting, immunohistochemistry, and intracellular calcium concentration measurement were used. RESULTS: The authors found elevated mAChRs expression in the postoperative pain model. Antagonizing mAChRs reduced pain sensitivity and attenuated the IP3-Ca2+-CaM pathway. Remarkably, electroacupuncture treatment further mitigated pain, potentially by suppressing this signaling cascade. INTERPRETATION: These findings reveal a novel connection between mAChRs and the IP3-Ca2+-CaM pathway in postoperative anal pain and suggest electroacupuncture as a promising avenue for pain relief through these mechanisms, offering insights into innovative strategies for postoperative pain management.

Anti-angiogenic activity of polymeric nanoparticles loaded with ursolic acid.

Ursolic acid (UA) is an abundant natural product and has shown great promise for treating diseases related to the appearance of new blood vessels. However, its clinical use is limited due to its low solubility in aqueous media, resulting in reduced bioavailability. The present study aimed to synthetize poly(lactic-co-glycolic acid) nanoparticles loaded with UA by nanoprecipitation method and to evaluate the toxicity and anti-angiogenic activity using the in vivo chorioallantoic model. The nanoparticles were obtained in the size range that varied from 103.0 to 169.3 nm, they presented a uniform distribution (polydispersity index <0.2), and a negatively charged surface, with an encapsulation efficiency close to 50%. The release profile of the developed nanoformulation showed an initial burst in the first 2 h and demonstrated no acute toxicity (irritation index <0.9). Moreover, the chorioallantoic assay showed a significant reduction in both geometrical and topological parameters compared to saline control (p < .05). In conclusion, the study revealed a quick and simple way to obtain poly(lactic-co-glycolic) acid nanoparticles, a drug delivery system to UA, which showed potential antiangiogenic action and can be used to treat diseases involving neovascularisation.

Does the surface conditioning of glass and hybrid ceramics with self-etching silane present a bond strength similar to that of conventional bonding? Systematic review and meta-analysis of in vitro studies.

PURPOSE: To evaluate, through in vitro studies, the bond strength of vitreous and hybrid ceramics with self-etching surface treatment compared to conventional treatment. METHODS: This systematic review followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) and was registered on the open science framework (OSF) platform for in vitro studies. A population, intervention, control, and outcome (PICO) question was formulated: "Does the surface conditioning of glass and hybrid ceramics with self-etching silane present a bond strength similar to that of conventional bonding?". A literature search was carried out in the PubMed, Embase, Web of Science, Cochrane Library, and ProQuest databases until September 2023. The Joanna Briggs Institute (JBI) critical appraisal guidelines for quasi-experimental studies were used for risk assessment of bias. The meta-analysis was based on the inverse variance (IV) method (p < 0.05). RESULTS: A total of 29 in vitro studies published between 2017 and 2022 were included in this systematic review, totaling 1889 ceramic samples. The meta-analysis indicated a significant decrease in the bond strength of HF 4%-5% with silane compared to self-etching (p < 0.05; MD: 0.34; 95% CI: 0.13-0.35; I2 = 3%, p = 0.42), while it indicated that there was no significant difference between self-etching compared to 9%-10% HF with silane (p = 0.92; MD: 0.02; 95% CI: -0.32 to 0.36; I2 = 14%, p = 0.32). CONCLUSION: Self-etching primer presents bond strength that is superior to or similar to conventional surface treatment on glass and hybrid ceramics.

Modified Surgical Guide for Root Sectioning in the Socket Shield Technique-In Vitro Study.

OBJECTIVE: This in vitro study aimed to evaluate the effectiveness of a printed surgical guide for root sectioning in the socket-shield technique. MATERIALS AND METHODS: A typodont model of the maxilla with augmented filler was used for the upper right central incisor, and CBCT images were obtained. Two types of vertical root sectioning guides were tested: one with a buccal sleeve (Group A, n = 10) and another with a buccal orientation slit (Group B, n = 10). Control group (n = 10) performed freehand cuts on printed models. After crown cutting with diamond burs, root sectioning was conducted using an ultrasonic tip with the guides. Mean and standard deviation were calculated for the remaining root length, width, and volume. Data were analyzed using the Kruskal-Wallis test and Dunn's post hoc test. RESULTS: Statistical analysis showed significant differences in root width between the control group (2.0 mm) and both Groups A (2.655 mm; p < 0.0001) and B (2.460 mm; p < 0.0001). Group B (5.585 mm) also showed a significant difference in root remnant compared with the control (13.880 mm; p < 0.0043). Groups A and B did not differ significantly from each other. CONCLUSIONS: The socket shield technique is safe and effective, this study aimed to add improvements through the introduction of surgical guides, facilitating the root section, which is the critical phase so that the parameters that are requisite for success are achieved in terms of width, length, and volume of the root remnant. Both guided techniques effectively facilitated root sectioning, maintaining satisfactory root thickness and length. CLINICAL SIGNIFICANCE: Sectioning the root is challenging for the correct angulation to remove the palatal portion in the socket shield technique. Therefore, modifying this technique with the use of the presented guides, it is possible to prevent damage to the soft tissues and to plan the surgery with the help of cone beam computed tomography (CBCT) scans to remove the root apex and maintain the root remnant with a thickness greater than 1.5 mm, making the socket-shield technique more predictable.

Microstructural and flexural strength of various CAD-CAM lithium disilicate ceramics.

PURPOSE: To analyze the microstructural and mechanical properties of various commercial trademarks of lithium disilicate ceramics for CAD-CAM systems. MATERIALS AND METHODS: Specimens of different lithium disilicate ceramics were obtained and randomized into 5 groups (n = 14): EM: e.max CAD; RT: Rosetta SM; EV: Evolith; PM: Smile-Lithium CAD; and, HS: HaHaSmile. The microstructural analysis was performed by X-ray diffraction (XRD) and scanning electron microscopy (SEM); for flexural strength, the three-point bending flexure test was used. XRD and SEM data were qualitatively evaluated. Data from flexural strength were assessed with one-way ANOVA test (α = 0.05) and Weibull analysis. RESULTS: High peaks corresponding to the lithium metasilicate and lithium disilicate pattern with similar intensities were observed in all ceramics in the XRD analysis. SEM images showed similar patterns of crystalline structure in the EM and RT ceramics, while the other three groups presented different crystal morphologies than the previous ones and were similar to each other. No differences were found in flexural strength among the groups (p = 0.28). CONCLUSIONS: The CAD-CAM lithium disilicate ceramics showed comparable crystalline intensities. The microstructure of the EM and RT ceramics were different from the other groups. Flexural strength was similar among all ceramics.

Effectiveness of different surface treatments on bond strength between 3D-printed teeth and denture base.

PURPOSE: To investigate the effects of different surface treatments and thermal cycling on the shear bond strength between 3D-printed teeth and denture bases. MATERIAL AND METHODS: For the shear bond strength (SBS) test, the specimens were the maxillary central incisors (11 × 9 × 7 mm) bonded on a cylindrical base (20 × 25 mm). The control group was heat-cured polymethylmethacrylate (PMMA) (N = 20). The printed group was divided into five subgroups (N = 20): no treatment, sandblasting with aluminum oxide (Al2O3), methyl methacrylate monomer, acetone, and adhesive with urethane dimethacrylate. Half of the samples were subjected to 2000 thermal cycling cycles, and all samples were subjected to the SBS test. The failure mode was established as adhesive, cohesive, or mixed through stereomicroscopic analysis. The surface roughness test (Sa) was performed using optical profilometry, and the rectangular specimens (14 × 14 × 2.5 mm) were divided into four groups according to the surface treatments (N = 7 per group). Paired T and Wilcoxon tests were conducted to perform comparisons within the same group. The Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner post-hoc tests were conducted to compare the groups. RESULTS: Al2O3 sandblasting in the 3D-printed groups achieved high SBS values comparable to those of the control group in the thermal cycled (p = 0.962) and non-thermal cycled samples (p = 0.319). It was the only treatment capable of modifying the surface of the 3D-printed resin, thereby increasing the roughness (p = 0.016). CONCLUSIONS: Sandblasting is recommended to increase the bond strength between the tooth and denture bases.

Exploring the optical behavior and relative translucency parameter of CAD-CAM resin-based composites, polymer-infiltrated ceramic network, and feldspar porcelain.

OBJECTIVES: To evaluate and compare the optical properties and relative translucency parameter of CAD-CAM restorative materials. METHODS: Four CAD-CAM materials were evaluated: Lava Ultimate (LU), Grandio Blocs (GB), VITA Enamic (VE), and VITA Mark II (VM). Disk-shaped samples in shade A2-HT were prepared (n = 10) and polished to 1.00 ± 0.01 mm of thickness. Scattering (S), absorption (K), albedo (a) coefficient, transmittance (T%), light reflectivity (RI), infinite optical thickness (X∞), and radiative transfer coefficients (µa, and µ'S) were calculated using Kubelka-Munk method and Thennadil's semi-empirical approach. Root Mean Square Error (RMSE) and Goodness of Fit (GFC) were used as performance optical behavior. Translucency differences were evaluated using the relative translucency parameter (RTP00) and 50:50 % translucency perceptibility and acceptability thresholds (TPT00 and TAT00). RESULTS: The spectral distribution of S, K, T%, RI, and X∞ was wavelength-dependent. GFC and RMSE values indicated good spectral behavior matches and good comparative spectral values for RI in LU-GB, LU-VE, and GB-VE, and for K in VE-VM. VM displayed the highest scattering values across the wavelengths, while VE and VM showed lower absorption at shorter wavelengths. LU and GB had the highest transmittance. The X∞ values indicated that all 1.0 mm thick materials could be influenced by the background. No good spectral match and no good comparative spectral values were found between CAD-CAM materials and anterior bovine maxillary specimens. VM had the lowest RTP00 values with perceptible and unacceptable differences compared to CAD-CAM materials evaluated. SIGNIFICANCE: Understanding the optical behavior of different CAD-CAM materials was essential for guiding clinicians in material selection and optimizing their clinical performance. The findings confirm that the different compositions and microstructure impact the optical properties and translucency of CAD-CAM restorative materials.

Influence of microstructure on optical properties of CAD-CAM lithium disilicate glass-ceramics.

OBJECTIVES: To evaluate the influence of microstructure and chemical composition on the optical properties of CAD-CAM lithium disilicate glass-ceramics. METHODS: Samples (n = 5; 1.0 mm thickness) of shades A1, A2, and A3 were fabricated from CAD-CAM ceramic blocks (Ivoclar Vivadent): IPS e.max® CAD LT (emLT) and HT (emHT). Samples were polished to 1.0 ± 0.01 mm in thickness. The optical properties (R- reflectance; T- transmittance; µs'- reduced scattering and µa- absorption coefficients) from the post-crystallized samples were determined using the inverse adding-doubling (IAD) method based on integrating-sphere measurements. Additionally, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used to evaluate the microstructural properties. Energy-dispersive X-ray (EDX) was employed to analyze the chemical composition. The chemical and structural characterization were performed before and after crystallization of the ceramic samples. RESULTS: emLT showed higher values of µs'and lower values of µa and T than emHT for each shade in all wavelengths (p < 0.003). Considering T for emHT, there were no statistical differences for shades A1 and A2 at 488 nm and 514.5 nm (p > 0.003) and shades A1 and A3 at 457.9 nm (p > 0.003). emLT showed particle length ranging from 0.74 to 2.78 µm (mean = 1.57 µm and RF-relative frequency = 28 %) and particle width ranging from 0.21 to 0.74 µm (mean = 0.30 µm and RF = 31 %). emHT showed particle length ranging from 0.83 to 3.08 µm (mean = 1.86 µm and RF = 21 %) and particle width ranging from 0.24 to 1.12 µm (mean = 0.56 µm and RF = 28 %). In comparison with emHT, emLT showed greater vol% for C, K, and Zr and lower vol% for O and Al. SIGNIFICANCE: The optical properties of CAD-CAM lithium disilicate glass-ceramics are influenced by the chemical composition and, consequently, by the material microstructure.

Effect of temporary cement on the color of temporary crowns made by conventional pressing methods and substractive CAM/CAD technologies / Efecto del cemento temporal sobre el color de las coronas temporales realizadas mediante métodos de prensado convencionales y tecnologías sustractivas CAM/CAD

Abstract The color stability of temporary restoration is crucial, especially in sensitive areas in terms of aesthetics. This research aimed to determine the effect of temporary cement on the color of temporary crowns made by conventional pressing methods (indirect) and CAM/CAD technologies using milling machines and 3D printers. This study was carried out in a laboratory, utilizing A2 color in all manufacturing methods. The color of the restorations was measured by a spectrophotometer after cementation with semi-permanent resin cement. Subsequently, color changes of the samples (ranging from 0 to 100) were calculated using the Commission International de l'Eclairage (CIE) Lab system. Data analysis was based on descriptive statistics methods and statistical tests, including one-way analysis of variance (ANOVA) and Tukey's post hoc test. According to the results of ANOVA, there was a significant difference between the three groups in terms of the 'a' and 'b' indexes (P<0.001). However, regarding the 'l' index, no significant difference was observed among the three groups (P=0.250). Also, based on Tukey's post hoc test, a significant relationship was seen between the first and second pairs in the 3D printer group, and between the first and third pairs in the milling group (P<0.001). However, no significant difference was observed in the conventional pressing group. The results showed that the 3D printing method exhibited the highest amount of color change among the three methods, while the milling method demonstrated the lowest amount of change.

Resumen La estabilidad del color de la restauración temporal es muy importante, especialmente en zonas sensibles desde el punto de vista estético. En la presente investigación, el objetivo fue determinar el efecto del cemento temporal sobre el color de coronas temporales realizadas mediante métodos de prensado convencionales (indirectos) y tecnologías CAM/CAD utilizando fresadora e impresora 3D. Este estudio se llevó a cabo en un laboratorio y se utilizó color A2 en todos los métodos de fabricación. El color de las restauraciones se midió mediante un espectrofotómetro después de cementarlas con cemento de resina provisional. Luego se calcularon los cambios de color de las muestras (de 0 a 100) utilizando el sistema CIE Lab. El análisis de los datos se basó en métodos de estadística descriptiva y pruebas estadísticas, incluido el análisis de varianza unidireccional (ANOVA) y la prueba post hoc de Tukey. Según los resultados del análisis de varianza unidireccional, hubo una diferencia significativa entre los tres grupos en términos de los índices a y b (P<0,001), pero en términos del índice l, no hubo diferencias significativas entre los tres grupos (P=0,250). Además, según la prueba post hoc de Tukey, se observó una relación significativa entre el primer y el segundo grupo de impresoras 3D y entre el primer y el tercer grupo de fresado (P<0,001). Sin embargo, no se observó ninguna diferencia significativa en el grupo de prensado convencional. Los resultados mostraron que el mayor cambio de color entre los tres métodos fue con el método de impresión 3D, y la menor cantidad fue con el método de fresado.

A Survey of Preferences for Ceramic Materials on Tooth-Supported Crowns Among Dental Practitioners in Chile.

Purpose: To evaluate the preferences of dental practitioners for tooth-supported crowns dental ceramics by means of an online survey and to assess the influence of age, gender, years of experience, and dental specialty on those preferences. Materials and Methods: An anonymous questionnaire was delivered online through Google Surveys, targeting 796 dentists. It contained 17 dichotomous, closed questions with two sections. The first section dealt with general characteristics, including age, gender, years of experience, training in prosthodontics, and hours worked per week. The second section included questions regarding preferences of different materials for crowns, and the use of digital workflows. Analyses were carried out with Stata 14.0 software (StataCorp, TX, USA). A significance level of p=0.05 was adopted. Results: 248 surveys were answered. Practitioners in Chile preferred lithium disilicate for the anterior region (55.2%) but also for the posterior area (40.7%), regardless of their age, gender, years since graduation, hours worked per week or any training in prosthodontics. Chilean dentists over 50 years old considered zirconia almost 4 times more than those under 30 years old for anterior crowns (51.85%). 59.68% of dentists take digital impressions, and 37.10% have access to chairside CAD/CAM technology. In this group, 54.4% preferred feldspathic ceramic for anterior and 23.9% for posterior crowns. Conclusions: While there is a wide range of dental ceramic materials, these results provide a snapshot of the current trends in Chile where lithium disilicate is the most preferred ceramic material for tooth-supported crowns, and metal-ceramic is the least preferred material.

Crowdfunding for Complementary and Alternative Cancer Treatments in Tijuana, Mexico: Content Analysis.

BACKGROUND: Complementary and alternative (CAM) cancer treatment is often expensive and not covered by insurance. As a result, many people turn to crowdfunding to access this treatment. OBJECTIVE: The aim of this study is to identify the rationales of patients with cancer seeking CAM treatment abroad by looking specifically at crowdfunding campaigns to support CAM cancer treatment in Tijuana, Mexico. METHODS: We scraped the GoFundMe.com and GiveSendGo.com crowdfunding platforms for campaigns referencing CAM cancer clinics in Tijuana, initiated between January 1, 2022, and February 28, 2023. The authors created a coding framework to identify rationales for seeking CAM treatment in Tijuana. To supplement campaign metadata, we coded the beneficiary's cancer stage, type, age, specific treatment sought, whether the beneficiary died, gender, and race. RESULTS: Patients sought CAM cancer treatment in Tijuana because the (1) treatment offers the greatest efficacy (29.9%); (2) treatment offered domestically was not curative (23.2%); (3) the clinic treats the whole person, and addresses the spiritual dimension of the person (20.1%); (4) treatments are nontoxic, natural, or less invasive (18.2%); and (5) clinic offers the newest technology (8.5%). Campaigns raised US $5,275,268.37 and most campaign beneficiaries were women (69.7%) or White individuals (71.1%). CONCLUSIONS: These campaigns spread problematic misinformation about the likely efficacy of CAM treatments, funnel money and endorsements to CAM clinics in Tijuana, and leave many campaigners short of the money needed to pay for CAM treatments while costing beneficiaries and their loved one's time, privacy, and dignity. This study affirms that Tijuana, Mexico, is a very popular destination for CAM cancer treatment.

A Novel Device for the Evaluation of In Vitro Bacterial Colonization in Membranes for Guided Tissue and Bone Regeneration.

Purpose: To evaluate, in vitro, the efficiency of a novel apparatus to test the adherence and penetration of bacteria on different membranes for guided regeneration. Methodology: To create the 3D device, Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) systems were used. Three types of biomaterials were tested (n = 6): (DT) a collagen membrane; (DS) a polymer membrane; and (LP) a dense polytetrafluoroethylene barrier. The biomaterials were adapted to the apparatuses and challenged with two different monospecies bacterial culture of A. actinomycetemcomitans b and S. mutans. After 2 h, bacterial adherence and penetration were quantified by counting the number of colony-forming units (CFUs). Two specimens from each group were used for image analysis using Confocal Laser Scanning Microscopy. Statistical analysis was performed. Findings: The DS group had a higher adherence of S. mutans compared to A. actinomycetemcomitans b (p = 0.05). There was less adherence of A. actinomycetemcomitans b in the DS group, compared to the LP (p = 0.011) and DT (p < 0.001) groups. Only the membranes allowed penetration, which was blocked by barriers. The DT group allowed a greater penetration of S. mutans to occur compared to A. actinomycetemcomitans b (p = 0.009), which showed a higher penetration into the DS membranes compared to S. mutans (p = 0.016). The penetration of A. actinomycetemcomitans b through DS was higher compared to its penetration through DT and LP (p < 0.01 for both). DT and DS allowed a greater penetration of S. mutans to occur compared to LP, which prevented both bacterial species from penetrating. Conclusion: The apparatus allowed for the settlement and complete sealing of the biomaterials, enabling standardization.

Impact of CAD/CAM burs lifetime on surface properties of dental zirconia: Implications for biocompatibility of custom abutments.

OBJECTIVE: To evaluate the effect of the deterioration of computer aided design/computer aided manufacturing (CAD/CAM) burs during zirconia milling, on surface roughness, contact angle, and fibroblast viability. MATERIALS AND METHODS: Ceramic blocks were milled and 75 ceramic disks (8 × 1.5 mm) made and allocated into three groups (n = 25): G1-brand new 2L and 1L burs, G2-2L bur at the end of lifetime and brand new 1L bur and G3-both burs at the end of their lifetimes. Roughness (Ra, Rq, and Rz) was evaluated using a 3D optical profilometer, the contact angle by the sessile drop method and the cell viability of the mouse NIH/3T3 fibroblast, using the Alamar Blue assay at intervals of 24, 48, and 72 h (ISO 10993-5). Data were analyzed by one-way ANOVA and Kruskal-Wallis tests (p ≤ 0.05). RESULTS: Roughness increased as the burs deteriorated and G3 (0.27 ± 0.04) presented a higher value for Ra (p < 0.001). The highest contact angle was observed in G3 (86.2 ± 2.66) when compared with G1 (63.7 ± 12.49) and G2 (75.3 ± 6.36) (p < 0.001). Alamar Blue indicated an increase in cell proliferation, with no significant differences among the groups at 24 and 72 h (p > 0.05). CONCLUSIONS: The deterioration of the burs increased the surface roughness and decreased the wettability, but did not interfere in cell viability and proliferation. CLINICAL SIGNIFICANCE: The use of custom zirconia abutments represents an effective strategy for single crowns restorations. Our findings suggest that these abutments can be efficiently milled using CAD/CAM burs within their recommended lifetime.

Oenothein B from Eugenia uniflora leaves exerts pro-angiogenic effects by increasing VEGF and TNF-α levels.

Oenothein B (OeB), a dimeric ellagitannin with a macrocyclic structure, is reported to have beneficial effects, including antioxidant, antitumor, antiviral, and antimutagenic effects, on human health. Despite the remarkable properties of OeB, its role in neovascularization process has not yet been evaluated. Thus, this study aimed to evaluate the angiogenic activity of OeB using a chorioallantoic membrane (CAM) assay at different concentrations (6.25, 12.5, and 25 µg/µL), employing digital imaging and histological analysis. Furthermore, to elucidate the mechanisms by which OeB influences angiogenesis, we assessed the levels of vascular endothelial growth factor (VEGF) and tumor necrosis factor-alpha (TNF-α) in CAM using immunohistochemical analysis. All concentrations of OeB significantly increased (p < 0.05) the percentage of vascularization as well as the levels of all the angiogenesis-associated parameters evaluated, indicating the pronounced pro-angiogenic activity of OeB. Our results showed that inflammation was one of the most relevant phenomena observed in CAM histology along with angiogenesis. In addition, a significant increase in VEGF and TNF-α levels was observed in all the CAMs compared to the negative control (p < 0.05). We suggest that OeB may induce the presence of inflammatory cells in CAM, leading to increased VEGF and TNF-α levels that result in the induction of angiogenesis. Therefore, OeB presents a favorable profile that could be further explored for the development of drugs for pro-angiogenic and tissue repair therapies.

Effect of polishing and bleaching on color, whiteness, and translucency of CAD/CAM monolithic materials.

OBJECTIVE: To evaluate the effect of polishing and bleaching on the recovery of lightness, color, whiteness, and relative translucency parameter (RTP) in CAD/CAM materials and changes in these properties when another staining in coffee was conducted after the treatments. MATERIALS AND METHODS: Disks of Lava Ultimate (LU), Vita Enamic (VE), IPS Empress CAD (EMP), IPS e.max CAD (EMAX), and Vita Suprinity (VS) were (1) not treated (control), (2) polished with Proxyt or (3) Ceramisté, (4) bleached with Opalescence PF or (5) Whiteness HP Blue, and (6) air polished with Clinpro Prophy Powder. CIE L*a*b* color coordinates were registered at baseline (R0), after staining with coffee for 30 min daily for 36.5 days and treatment (R1), and after another staining (R2). Differences (R1-R0 and R2-R0) in lightness (ΔL00), color (ΔE00), RTP (ΔRTP00), and whiteness (ΔWID) were evaluated by mixed repeated measures ANOVA and 95% confidence intervals (α = 0.05) and interpreted in function of their respective 50:50% PT and AT thresholds. Topography was evaluated by scanning electron microscopy (SEM). RESULTS: In LU, Opalescence PF and Proxyt decreased Δ L 00 R 1 - R 0 $$ {\Delta L}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ , Δ E 00 R 1 - R 0 $$ {\Delta E}_{00\left({R}_1\hbox{--} {\mathrm{R}}_0\right)} $$ , and ΔWI D R 1 - R 0 $$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_1\hbox{--} {R}_0\right)} $$ and showed lower Δ L 00 R 2 - R 0 $$ {\Delta L}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ , Δ E 00 R 2 - R 0 $$ {\Delta E}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ , and ΔWI D R 2 - R 0 $$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_2\hbox{--} {R}_0\right)} $$ . In VE, all treatments decreased Δ L 00 R 1 - R 0 $$ {\Delta L}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ , Δ E 00 R 1 - R 0 $$ {\Delta E}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ , and ΔWI D R 1 - R 0 $$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_1\hbox{--} {R}_0\right)} $$ , whereas Δ L 00 R 2 - R 0 $$ {\Delta L}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ , Δ E 00 R 2 - R 0 $$ {\Delta E}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ , and ΔWI D R 2 - R 0 $$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_2\hbox{--} {R}_0\right)} $$ were lower in Opalescence PF than in the control group. In both moments, ΔE00 and ΔWID in EMP (also ΔL00) and EMAX were higher in Opalescence PF than in the control group, from which the other treatments did not differ in R1-R0. In EMP, Δ E 00 R 2 - R 0 $$ {\Delta E}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ in Whiteness HP Blue (also Δ L 00 R 2 - R 0 $$ {\Delta L}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ ) and Proxyt were also higher in comparison to the control group and in VS, Ceramisté decreased Δ L 00 R 1 - R 0 $$ {\Delta L}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ , Δ E 00 R 1 - R 0 $$ {\Delta E}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ , and Δ R T P 00 R 1 - R 0 $$ \varDelta RT{P}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ , whereas Opalescence PF increased ΔRTP 00 R 1 - R 0 $$ {\Delta \mathrm{RTP}}_{00\left({R}_1\hbox{--} {R}_0\right)} $$ . Δ E 00 R 2 - R 0 $$ {\Delta E}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ of Ceramisté and ΔWI D R 2 - R 0 $$ {\Delta \mathrm{WI}}_{\mathrm{D}\left({R}_2\hbox{--} {R}_0\right)} $$ and Δ R T P 00 R 2 - R 0 $$ \varDelta RT{P}_{00\left({R}_2\hbox{--} {R}_0\right)} $$ of Proxyt were lower than those of the control group. CONCLUSIONS: The most suitable treatment to recover the lightness, color, whiteness, and RTP without changing these properties after another coffee exposure is material-dependent. CLINICAL SIGNIFICANCE: Although the effectiveness of the treatment was material-dependent, Proxyt was the only treatment that promoted clinically acceptable changes for both LU and VE, while for purely ceramic materials, this condition was observed with Ceramisté and Clinpro Prophy Powder.

Effect of the CAD/CAM Milling Protocol on the Fracture Behavior of Zirconia Monolithic Crowns.

Although advancements in CAD/CAM technology allow for more personalized treatments, it is not clear how modifications in the CAD/CAM milling process could affect the restoration surface conditions and their mechanical behavior. The objective of this study was to evaluate the effect of different CAD/CAM milling protocols on the topography and fracture behavior of zirconia monolithic crowns (3Y-PSZ) subjected to a chewing simulation. Monolithic 3Y-PSZ premolar crowns were milled using three protocols (n = 13) (slow (S), normal (N), and fast (F)). Crowns were cemented on a dentin analog abutment and subjected to mechanical aging (200 N, 2 Hz, 1,500,000 cycles, 37 °C water). Surviving crowns were subjected to compressive load test and analyzed using fractography. Fracture load data were analyzed with two-parameter Weibull analysis. The surface topography of the crowns was examined with a stereomicroscope and a 3D non-contact profiler. All crowns survived the chewing simulation. Crowns milled using the F protocol had the greatest characteristic fracture load, while crowns produced with the S protocol showed high Weibull modulus. Groups N and S had a more uniform surface and detailed occlusal anatomy than group F. The CAD/CAM milling protocol affected the topography and mechanical behavior of 3Y-PSZ monolithic crowns.

Resistance of CAD/CAM composite resin and ceramic occlusal veneers to fatigue and fracture in worn posterior teeth: A systematic review.

Severe tooth wear is related to substantial loss of tooth structure, with dentin exposure and significant loss (≥1/3) of the clinical crown. The objective of this systematic review was to summarize and analyze the scientific evidence regarding the mechanical performance of computer-aided design/computer-aided manufacturing (CAD/CAM) composite resin and CAD/CAM lithium disilicate ceramic occlusal veneers, in terms of fatigue and fracture resistance, on severely worn posterior teeth. Currently, occlusal veneers are an alternative for treating worn posterior teeth. Although scientific evidence demonstrates the good performance of lithium disilicate occlusal veneers, there are less brittle materials with a modulus of elasticity more similar to dentin than ceramics, such as resin CAD/CAM blocks. Therefore, it is important to identify which type of material is best for restoring teeth with occlusal wear defects and which material can provide better clinical performance. This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive search of the PubMed, Embase, Web of Science, Scopus, Cochrane, OpenGrey, Redalyc, DSpace, and Grey Literature Report databases was conducted and supplemented by a manual search, with no time or language limitations, until January 2022. We aimed to identify studies evaluating the fatigue and fracture resistance of CAD/CAM composite resin and ceramic occlusal veneers. The quality of the full-text articles was evaluated according to the modified Consolidated Standards of Reporting Trials (CONSORT) criteria for in vitro studies, and 400 articles were initially identified. After removing duplicates and applying the selection criteria, 6 studies were included in the review. The results demonstrated that the mechanical performance of CAD/CAM composite resin occlusal veneers is comparable to that of CAD/CAM lithium disilicate occlusal veneers in terms of fatigue and fracture resistance.

Activated AMP-protein kinase (pAMPK) is overexpressed in human somatotroph pituitary adenomas.

INTRODUCTION: AMPK (AMP-activated protein kinase) is an enzyme that acts as a metabolic sensor and regulates multiple pathways via phosphorylating proteins in metabolic and proliferative pathways. The aim of this work was to study the activated cellular AMPK (phosphorylated-AMPK at Thr172, pAMPK) levels in pituitary tumor samples from patients with sporadic and familial acromegaly, as well as in samples from normal human pituitary gland. METHODS: We studied pituitary adenoma tissue from patients with sporadic somatotroph adenomas, familial acromegaly with heterozygote germline variants in the aryl hydrocarbon receptor interacting protein (AIP) gene (p.Q164*, p.R304* and p.F269_H275dup) and autopsy from normal pituitary glands without structural alterations. RESULTS: Cellular levels of pAMPK were significantly higher in patients with sporadic acromegaly compared to normal pituitary glands (p < 0.0001). Tissues samples from patients with germline AIP mutations also showed higher cellular levels of pAMPK compared to normal pituitary glands. We did not observe a significant difference in cellular levels of pAMPK according to the cytokeratin (CAM5.2) pattern (sparsely or densely granulated) for tumor samples of sporadic acromegaly. CONCLUSION: Our data show, for the first time in human cells, an increase of cellular levels of pAMPK in sporadic somatotropinomas, regardless of cytokeratin pattern, as well as in GH-secreting adenomas from patients with germline AIP mutations.

Intra-radicular retention with custom designed CAD-CAM fibRe-reinforced composite post-core: a dental technique.

A technique is outlined for utilising a polymeric composite reinforced with glass fibres in a three-dimensional mesh as a post-core in aesthetic cases. The clinical procedure involves obtaining an impression of the root canal space, scanning the definitive cast, and milling a fibre-reinforced composite post-core. Subsequently, the intra-radicular post-core is cemented using an adhesive resin cement. The use of custom-made computer-aided design-computer-aided manufacturing (CAD-CAM) fibre-reinforced composite post-core facilitates repairability, provides better adaptation to the root canal space, avoids uneven cement thickness, ensures chemical adhesion to resin cement, and promotes favourable aesthetics when combined with all-ceramic crowns.